It is known that in rigid sport footwear with a central entrance, such as for example ski boots, whether for Alpine skiing, snowboarding or suchlike, the cuff and the shell are pivoted to each other in correspondence with the malleolar zone of the foot, and can assume a first clamped position for use during sport, to clamp the ankle during activity, and a second, unclamped position to facilitate walking, putting on and removing the boot.
Such boots are provided with clamping and unclamping devices which allow to modify the reciprocal coupling condition of the cuff and shell.
Known clamping and unclamping devices normally consist, however, of complex and bulky mechanisms that use gears, tie rods, pins or keys: this entails an increase in the production costs of the boot, laborious maneuvers and exposure to wear, with the risk of accidental unclamping.
The patents IT-B-1.336.330, IT-B-1.369.969, IT-B-1.370.304, IT-B-1.374.307, IT-B-1.370.337 and IT-B-1.389.364 in the name of the present Applicant are also known. These describe improved solutions to the state of the art, where generally a stop element or strut is provided, mounted on the cuff by pivoting or sliding. The stop element is mobile between a first clamped position, in which it cooperates with a clamping surface of the shell to keep the cuff in a determinate clamped position with respect to the shell, and a second unclamped position, in which it is freed from the clamping surface of the shell, to allow the cuff to oscillate freely with respect to the shell.
The passage of the strut between the first and the second position is normally determined by manual action on a respective lever element protruding from the cuff and connected to the strut by means of various types of drive kinematisms, which are particularly complex and costly since they are formed by a high number of components which must be assembled, which are delicate and therefore subject to breakage, where one or more elastic means are typically used, such as torsional springs or return springs that facilitate the passage between the two positions described above.
Document DE-A-2.404.447 describes a ski boot that provides an elastic sheet associated with the cuff by means of an additional assembly block, and a lever anchored to the shell, with a clamping function in several positions, but which does not intervene in the clamping operation, acting directly on the elastic sheet.
Document U.S. Pat. No. 6,453,580 describes a cross-country skiing boot which provides a lever anchored to the cuff which, acting on a cable, puts under traction an extension in the cuff, which functions as an elastic element for absorbing impacts, and modifies its set-up.
Purpose of the present invention is to obtain a sport footwear that is simple and economical to produce, which can be put on and removed easily, and which solves the problems present in the state of the art, in particular obtaining a clamping device that is simple, reliable and formed by a limited number of components, so as to reduce production costs and also the possibility of breakage and hence the costs and frequency of repairs.
The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.